Pressure regulator with correlated relief valve



Oct. 19, 1965 P. J. NATHO 3,212,516

PRESSURE REGULATOR WITH CORRELATED RELIEF VALVE Original Filed Sept. 10,1962 3 Sheets-Sheet 1 my 2 v1 P/PEJJU/Qf JOU/PCf 3a m/ 7 INVENTOR. \25PAUL J. NATHO AGENT Oct. 19, 1965 P. .1. NATHO 3,212,516

PRESSURE REGULATOR WITH CORRELATED RELIEF VALVE Original Filed Sept. 10,1962 3 Sheets-Sheet 2 INVENTOR. 66 PAUL J. NATHO 0' BY if F/ r' W AGENTOct. 19, 1965 PRESSURE REGULATOR WITH CORRELATED RELIEF VALVE OriginalFiled Sept. 10, 1962 P. J. NATHO 3,212,516

S Sheets-Sheet 3 AGENT United States Patent 3,212,516 PRESSURE REGULATORWITH CORRELATED RELIEF VALVE Paul J. Natho, Houston, Tex., assignor toACF Industries, Incorporated, New York, N.Y., a corporation of NewJersey Original application Sept. 10, 1962, Ser. No. 222,275. Dividedand this application June 11, 1964, Ser. No. 374,468

7 Claims. (Cl. 137-116.5)

, This application is a division of my copending application SerialNumber 222,275 filed on September 10, 1962.

This invention relates to a system for the control of an offshore orother remotely located hydraulically operated valve and the essentialcomponents therefor.

The discovery of petroleum products in offshore and other isolatedlocations has resulted in changes of technology in the completion of thewell. In some instances, the wellhead control units are located abovethe surface of the water and the well is completed very much similar toa well located on land. However, in such instances, due to theinaccessibility of the location, the trend has been toward the use ofautomated equipment which can be automatically controlled from a centralpoint. In other cases, the wellhead control unit is located under thesurface of the Water, and in such cases it is necessary to use a newtechnology to complete the well. When the wellhead completion unit islocated under the water, the wellhead and control-system may be encasedin a canister isolating it from the sea water. It is desirable that thecontrol valves in the underwater Christmas tree be provided withautomatic fail-safe hydraulic operators which permit automated controlof the well. In both cases, the hydraulic lines to the automatedoperator may extend two or three miles from a control point. Due to thepressure of wells, it has been customary to use hydraulic operatorsdesigned to operate on a pressure of approximately 1000 p.s.i. Inasmuchas there is a large pressure drop in a hydraulic line of considerablelength, it has been found necessary to provide a large line to theoperator even though a large line is expensive. If a small line is used,line friction will result in a low rate of flow and a large pressuredrop, and consequently the initial pressure has to be considerablygreater than the pressure required at the operator to obtain a suitableflow rate, then when the hydraulic operator reaches the end of itsstroke and no more fluid is required, the initial pressure will bedeveloped which oftentimes is too great for the operator. Also, it iscustomary to use a single line system and rely on spring pressure tomove the valve to the other position. In using long lines it isdiflicult for the return spring in the operator to develop sufficientpressure to force back the hydraulic fluid in the short time usuallydesired for the operation of the valve since line friction in the linereduces the speed of movement of the hydraulic fluid. In order toovercome the objections of a small line, and the expense of a largeline, the present invention discloses a system which permits theutilization of a single small line without the possibility ofoverpressurization of the hydraulic operator to be controlled and whichpermits the utilization of a spring to operate the valve.

In order to accomplish the above, the control system of the presentinvention is comprised of a hydraulically operated valve requiring arelatively high pressure, for example in the neighborhood of 1000p.s.i., to operate the valve in one direction and having a spring ofsuflicient magnitude to move the valve to the other position uponrelease of pressure, a single small hydraulic line extending from theoperator, a pressure source capable of delivering at the operator apressue of at least 1000 p.s.i., a pressure regulator in the hydraulicline receiving the pres- 3,212,516 Patented Oct. 19, 1965 "ice sure fromthe pressure source and transmitting a constant pressure to thehydraulic operator. The pressure regulator has a relief valve to relieveany excess pressure. Also provided is a hydraulic unloading valvebetween the regulator and the hydraulic operator which receives thepressure from the regulator and transmits it to the operator while thepressure in the line is increased or maintained at the selectedoperating pressure and which dumps the hydraulic fluid rather thanreturning it to the pressure source when the pressure in the line isdecreased below a preset pressure. By dumping the hydraulic fluid closeto the hydraulic operator, it is possible to return the valve to theother position in a short period of time without the utilization of anextremely large and heavy spring.

In attempting to obtain units for the system, no commercial pressureregulator which included an internal relief adaptable for high pressurehydraulic service or a hydraulic unloading valve suitable for highpressure hydraulic service could be found. Accordingly, these two unitshad to be developed in order to permit the construction of the improvedcontrol system for automated valve operators.

The improved combined pressure regulator and internal relief valve issuitable for high pressure hydraulic service and permits the utilizationof a single small line which has an originating pressure high enough topermit a relatively large pressure drop in the line and yet develop atthe inlet of the regulator a pressure in excess of 1000 p.s.i. Theregulator transmits a regulated pressure to the operator. When theoperator has finished its stroke, the regulator prevents any buildup ofexcess pressure and retains the required pressure on the operator.Should the regulating valve leak to increase the pressure on theoperator, the included pressure relief valve which is set at a pressureapproximately p.s.i. above the operating pressure will function torelieve the excess pressure. The valve is simple in construction andinexpensive to manufacture.

The improved hydraulic unloading or dump valve delivers the pressurereceived from the pressure regulator to the operator. As long as thepressure is maintained on the inlet side of the dump valve, the fluidpressure is maintained on the operator and the dump port to the searemains closed. However, as soon as the pressure is lowered beyond a setpoint for any reason, the discharge valve opens and permits the fluid inthe operator to be discharged into the sea. Hydraulic fluid beingincompressible, it is necessary to remove only a very small amount offluid from the line to reduce the pressure thus eliminating the need forback flowing the fluid through the small line. The set dump pressure isstill sufficient to prevent any operator piston movement and resultingfluid flow when the pressure is reduced from the 1000 p.s.i. A novelsafety feature of this valve is that the fluid from the operator canreturn through the control line should the dump port to the sea becomeclogged for any reason. As previously mentioned, this would result in avery slow and undesirable valve operation only acceptable as anemergency measure. The unloading valve is simple in construction,inexpensive to manufacture and suitable for high pressure hydraulicservice.

As can be seen from the above, the principal object of the presentinvention is to provide a pressure regulator for use in a control systemfor an automated hydraulic operator which permits the utilization of asingle small line.

Another object is to provide an improved pressure regulator having aninternal relief valve suitable for high pressure hydraulic service.

Other and further objects of the invention will be obvious upon anunderstanding of the illustrative embodi- 'inlet and outlet ports 16 ofthe valve.

ments about to be described, or will be indicated in the appendedclaims, and various advantages not referred to herein will occur to oneskilled in the art upon employment of the invention in practice.

Preferred embodiments of the invention have been chosen for purpose ofillustration and description and are shown in the accompanying drawings,forming a part of the specification, wherein:

FIG. 1 is a schematic diagram of the control system of the presentinvention, with the valve being operated in open position.

FIG. 2 is a view similar to FIG. 1 with the valve closed.

FIG. 3 is a cross section of the pressure regulator of the controlsystem. The regulator valve being in the open position as in FIG. 1.

FIG. 4 is a fragmentary view of the valves of the pressure regulatorillustrated in FIG. 3 showing the regulator valve being in the closedposition.

FIG. 5 is a view similar to FIG. 4 with the relief valve being in theopen position.

FIG. 6 is a cross section of the unloading valve in the position shownin FIG. 1.

FIG. 7 is a view similar to FIG. 6 with the discharge valve open similarto the position in FIG. 2.

For the purpose of illustrating the invention, a hydraulically operatedreciprocating gate valve has been chosen since this type is the mostcommonly used valve for Wellhead service, however, any other type ofvalve capable of being operated by a hydraulic operator may becontrolled by the proposed system of this invention.

Referring now to the drawings, there is disclosed a fail safe closedhydraulically operated valve 10 which is controlled by the system of thepresent invention. The valve 10 is a reciprocating parallel expandinggate valve having a valve member 12 which reciprocates between the openand closed positions and expands in the fully open and fully closedposition to form a seal with seats 13. The valve member has a port 14 inthe upper portion thereof which in the open position is aligned with theExtending from the valve member 12 is a stem 18 which is attached to apiston 20 located in a cylinder 22 of a hydraulic operator 24.Surrounding the cylinder 22 is a spring 26 which is attached to theouter end of the stem 18. Surrounding the spring 26 is a cover 28 whichencloses the operator and seals all working parts from the elements. Theoperator 24 has a base 30 which is provided with a port 32 which leadsto the upper side of the cylinder 22. Hydraulic pressure applied to theupper side of the cylinder overcomes the force of the spring 26 andmoves the piston 20, stem 18 and valve member 12 axially inward so thatthe port 14 is aligned with the inlet and outlet ports 16. The valve 10is then in the open position. Release of the pressure in the upper partof the cylinder 22 permits the spring 26 to extend thereby moving thepiston 20, stem 18 and valve member 12 axially outward closing thevalve. In addition to the power of the spring 26, the fluid flowingthrough the valve will also act on the valve member 12 assisting inmoving the valve member 12 axially outward in the valve chamber.Attached to the port 32 in the base 30 of the operator 24 is a smallhydraulic line 34. The line 34 extends to a pressure source 36 which iscapable of delivering at the operator 24 hydraulic fluid having apressure of at least suflicient magnitude to operate the valve 10. Thepressure may be in the neighborhood of approximately 1000' p.s.i. whichhas been found to be suflicient in combination with the selectedcylinder size to operate the valve against the flow of fluids flowingthrough the valve. Located close to the pressure source 36 is athree-way control valve 37 which will direct pressure to the operator 24or will permit pressure from the operator to be discharged.

Positioned in the hydraulic line 34 near the operator 24 is a pressureregulator 38, see FIGS. 3, 4 and 5, which receives pressure from thepressure source 36 and transmits a regulated pressure. The housing ofthe pressure regulator is formed of two generally cylindrical sections4042 which are adjustably secured to each other by engagement of matingthreads 44.

The first section 40 of the pressure regulator 38 has an inlet port 46which is connected to the hydraulic line 34. The section 40 also has acylindrical chamber 48 in which is positioned a piston 50 having acircumferential seal 51 with the wall of the cylindrical chamber 48.Connecting the inlet port 46 and cylindrical chamber 48 is a passage 52in which is positioned a poppet regulator valve 54. Located in thepiston 50 is a poppet relief valve 56 having a portion 58 which contactsthe lower end 60 of the regulator valve 54. While it has been founddesirable to use poppet valves for the regulator and relief valve, othertypes of valves used to seal a passage maybe used if desired. Thesection 40 is also provided with an outlet port 62 which is incommunication with the cylindrical chamber 48 but is not incommunication, except through the cylindrical chamber 48, with the inletport 46. The second section 42 is provided with a heavy spring 64 whichbears against the piston 50 through a spring plate collar 65. Themagnitude of the spring 64 may be changed by the positioning of thesections 4042 relative to each other. The compression of the spring 64is so adjusted that the regulator valve 54 is normally held open untilthe pressure in the cylindrical chamber 48, and consequently at theoutlet port 62, reaches the maximum pressure required to operate thehydraulic operator 24, see FIG. 3. When this pressure is reached, thepressure in the cylindrical chamber 48 has built up sufliciently toovercome the action of the spring 64; therefore, piston 50 has moved asufficient amount that the portion 58 of the relief valve 56 whichnormally contacts the lower end of the regulator valve 54 moves out ofcontact with the regulator valve 54 and closes the regulator valve 54,see FIG. 4, allowing no further pressure to enter into the cylindricalchamber 48 and consequently flow out through the outlet port 62.Consequently, the pressure transmitted to the operator never exceeds theset limit. Also located in the section 42 is a central member 66 whichcontacts the relief valve 56 in the piston 50. The central member 66 isprovided with a discharge passage 68. Therefore, if the regulator valve54 leaks and hydraulic fluid flows into the cylindrical chamber 48moving the piston 50 further inward, the relief valve 56 is contacted bythe central member 66 and moved off its seat permitting any excesspressure to flow through the passage 68 in the central member 66 andoutward of the valve, see FIG. 5. The passage 68 may be provided with acheck valve 69 to permit flow outward of the valve only therebypreventing contamination from external fluid. The central member 66 ispositioned in a threadingly engaged member 70 in the end of the section42 so that the pressure at which the relief valve 56 will operate may beadjusted. The central member 66 will usually be so positioned so thatany pressure in excess of p.s.i. over the set operating pressure willcause the relief valve 56 to be opened relieving the excess pressurethrough the passage 68. To overcome packing friction, a small spring 71may be positioned around the central member 66 contacting the collar 65.By contacting a small collar 72 positioned about the central member 66,the spring 71 maintains the central member 66 against its pocket in thethreaded member 70 so that the central member 66 does not cause therelief valve 56 to be held open during pressure buildup therebydischarging pressure at a lower setting than desired. In order that theregulator valve 54 will close when the relief valve 56 is not.contacting it, there is a spring 74 between the top of the regulatorvalve 54 and the plug in the end of the housing- The regulator has twoadjustments. One, by adjusting: the sections 4042 of the housingrelative to each other the force of the spring 64 is adjusted. Thiscontrols the pressure at which the regulator valve will close. Thespring 64 resists the movement of the pislQu. 5. and in efiect regulatesthe pressure necessary for the piston 50 to move away from the regulatorvalve 54 whereby the end of the relief valve 56 will no longer contactthe regulator valve 54 and will permit the regulator valve 54' to beclosed by the spring 74. Accordingly, only pressure up to the set amountwill flow through the cylindrical chamber 48 and out through the outletport 62. Therefore, although the pressure source 36 may be located at agreat distance and of necessity, because of the line friction, have aninitial force much in excess to that required by the operator since theregulator 38 will cut olf the pressure at the set amount. Accordingly,the regulator may be built for much higher pressure application than theoperator. In the event that the regulator valve 54 should develop aleak, an additional saftey measure is provided in the regulator since ifthe pressure increases over a set amount, usually 100 p.s.i. above thenecessary operating pressure, the relief valve 56 will contact the endof the central member 66 and be moved from its seat thereby relievingany excess pressure through the passage 58 in the central member. Therelieving pressure may be adjusted by the positioning of the threadedmember 70 which moves the central member 66 relative to the end of therelief valve 56 which in effect determines how much further the piston50 has to move before the relief valve 56 is engaged by the centralmember 66, see FIG. 5.

Between the pressure regulator 38 and hydraulic operator 24 there ispositioned an unloading valve 76 which receives the pressure from thepressure regulator 38 and transmits it to the hydraulic operator 24while the pressure in the line 34 is being increased or maintained atthe selected operating pressure and which will dump the hydraulic fluidfrom the operator 24 when the pressure in the line 34 is decreasedbeyond a set pressure, see FIGS. 6 and 7. This permits the spring 26 inthe hydraulic operator 24 to move the valve member 12 to the otherposition in a short period of time since it does not have to overcomethe line friction of the hydraulic fluid moving in a small line.

The unloading valve 76 is formed of a housing 78 having an inlet port 80which receives the hydraulic line 34 coming from the outlet port 62 ofthe pressure regulator 38. In communication with the inlet port 80 is acylindrical chamber 82 in which is positioned a piston 84 which isprovided with a circumferential seal 86 sealing the inlet port 80 fromthe cylindrical chamber 82. The piston also has a second circumferentialseal 88 which seals the cylindrical chamber from the remaining portionof the housing. The piston 84 has a central passage at the inlet portend in which is located a poppet valve member 92. The piston has asec-0nd central passage 94 in which is located a stem 96. A seal 98 isprovided around the stem to prevent leakage of fluid into the remainingparts of the housing. The poppet valve member 92 has an extension 100which can be contacted by the stem to move the poppet valve member 92from its seat. As previously mentioned, poppet valves have been founddesirable; however, other types of valves known in the art to seal apassage may be used. The housing has an outlet port 102 whichcommunicates with the cylindrical chamber 82 but is sealed by thecircumferential seal 86 from the inlet port 80. The housing also has asecond port 104 which is also in communication with the cylindricalchamber 82 and is likewise sealed from the inlet port 80 by thecircumferential seal 86. The piston 84 has passages 106 whichcommunicate with the cylindrical chamber 82 adjacent the outlet passage102 and the second port 104. Therefore, when the poppet valve 92 isopened, there will be flow from the inlet port 80 through the centralpassage 90 and out through the ports 102-104, see FIG. 6. Surroundingthe stem 96 is a spring 108 which bears against the end of the piston 84through a spring plate 110. The other end of the spring 108 bearsagainst a portion 112 of the housing 78. As shown in thedrawing, portion112 of .the housing is threaded into the other portion of thehousbuildup, see FIG. 1.

ing and pressure adjusting shims 114 may be positioned between the endof the spring and the portion 112 of the housing. Also located aroundthe stem 96 is a piston stop 116 which permits a predetermined amount ofpiston movement. The unloading valve is also provided with a dischargepassage 118 in which is positioned a poppet valve 120 which is held inits seat by a light spring 122. A collar 124 is positioned around theend of the stem and contacts an extension 126 of the poppet valve tomove it off its seat in operating condition. The arrangement is suchthat when the pressure at the inlet port is not sufiicient to overcomethe action of the spring 108 the piston 84 will move toward the inletend of the housing and the collar 124 will bear against the extension126 of the poppet discharge valve moving it off its seat opening thedischarge valve 120, see FIG. 7. The housing 78 is provided with apassage 128 which communicates with the discharge passage 118. A line130 connects the second passage 104 with the passage 128 whereby, whenthe valve 92 is closed, flow from the outlet port 102 will flow throughthe second port 104 through the line 130 and out through the dischargepassage 118 and through check valve 132 to the atmosphere or sea. Thecheck valve 132 prevents back flow. This will quickly discharge anyfluid in the hydraulic operator 24 permitting the spring 26 to swiftlymove the piston 20 to the other end of the operator thereby operatingthe valve within the required period of time. If for some reason thedischarge passage 118 is blocked, the flow from the operator will flowthrough the outlet port 102 and will unseat the poppet valve 92 and willbe permitted to flow back through the inlet passage to the pressuresource and thereby the valve will operate, however, at a much slowerrate because of the line friction restraining the return flow of thehydraulic fluid.

Both the pressure regulator 38 and the unloading valve 76 are sodesigned that they may be vented to atmosphere, sea water or if desiredenclosed in a canister with the wellhead and operated against thepressure contained in the wellhead canister. These vents are 134 for theregulator 38 and 136 for the unloading valve 76. The vents 134 and 136may contain a check valve or be connected to a pressure source within awellhead canister.

As can be seen from the foregoing, the proposed control system shown inFIGS. 1 and 2 facilitates the completion of isolated wellheads andcontrol of other isolated hydraulically operated valves. It provides acontrol system permiting the utilization of small single hydraulic linefrom a central control point distant from the valve to be operated. Itutilizes an improved pressure regulator capable of operating withhydraulic fluid at relatively high pressure. The pressure regulator 38is so designed that the regulator valve 54 remains open during pressureWhen the pressure at the outlet port 62 of the pressure regulator 38exceeds the pressure set for operator function, the regulator valve 54closes preventing any further buildup of pressure to the operator, seeFIG. 4. Accordingly, it is only necessary for the operator 24 to bedesigned to handle the pressure range required for operation of thevalve that it is controlling. The pressure regulator is so designed thatthe pressure at the Outlet port 62 can be regulated over the rangenormally required by high pressure hydraulic operators. In addition thepressure regulator 38 is provided with a relief valve 56 which willfunction in the event that the regulator valve 54 leaks. In such event,any excess pressure will be discharged out of the regulator aflordingfurther protection to the hydraulic operator 24. Again the pressureregulator 34 is so designed that the pressure at which the relief valve56 will open can be independently set. The pressure regulator is alsoprovided with a port 134 which permits the internal housing to be ventedto either the atmosphere, sea water or an independent pressure source.In the line between the pressure regulator 38 and hydraulic operator 24is the unloading valve 76 which has two primary functions. One, duringpressure buildup and operation, the unloading valve 76 receives thepressure from the regulator 38 and transmits it to the hydraulicoperator 24, see FIG. 1. Second, upon decrease of pressure beyond a setpoint, the discharge valve 120 is opened dumping the hydraulic fluid inthe operator 24, see FIG. 2. Since hydraulic fluid is in effectincompressible, the relieving of a very small amount of fluid, by movingthe 3-way control valve 37 to discharge, will relieve the pressure inthe unloading valve 76 which will close the valve 92 allowing the spring108 to return the piston 84 and open the discharge valve 120 which willdump the hydraulic fluid in the operator 24 expeditiously. Such actionpermits fast action of the valve by the spring 26. If the hydraulicfluid in the cylinder 22 is not dumped close to the operator 24, therewill be a lag in operation as the line function of the fluid returningin the long line will substantially retard movement of the piston 20.However, as a safety feature the unloading valve 76 is so designed thatif the discharge passage 118 is blocked or the discharge valve 120becomes inoperative, the valve 92 is unseated and the hydraulic fluidcan flow back to the pressure source 36 where it can be discharged. Asmentioned, this would drastically lengthen the time required foroperation of the valve 10 and is only to be considered as an emergencymeans. As with the pressure regulator 38, the unloading valve 76 isprovided with means to permit adjustment of pressures and venting.

The control system of the present invention provides a means offacilitating operation of remotely located hydraulically operated valvespermitting use of an inexpensive small single control line yet at thesame time insuring that the operator receives only the required pressureand assure fast return operation by dumping the hydraulic fluid in theoperator near the operator eliminating time lag due to line friction.

As various changes may be made in the form, construction andarrangements of the parts herein without departing from the spirit andscope of the invention and without sacrificing any of its advantages, itis to be understood that all matter herein is to be interpreted asillustrative and not in a limiting sense.

I claim:

1. A pressure regulator for a control system for a hydraulicallyoperated valve, said regulator comprising: a housing formed of twogenerally cylindrical sections which are adjustably secured to eachother by means of mating threads; the first section having an inlet portwhich is in communication by a passage with a cylindrical chamber inwhich is positioned a piston, a poppet regulator valve in the passagebetween the inlet port and the cylindrical chamber, a poppet reliefvalve in the piston, the relief valve having a portion normallycontacting and holding open the regulator valve, an outlet port incommunication with the cylindrical chamber; the second section having aspring which bears against the piston and a central member whichcontacts the relief valve in the piston, the central member having adischarge passage, the magnitude of spring being adjustable bypositioning of the two sections relative to each other whereby theregulator valve remains open until the pressure in the cylindricalsection overcomes the magnitude of the spring at which time the reliefvalve moves out of contact with the regulator valve closing theregulator valve; upon any further increase in pressure in thecylindrical chamber the piston moves further into the chamber and therelief valve contacts the central member and relieves excess pressurethrough the discharge passage in the central member.

2. A pressure regulator for a control system for a hydraulicallyoperated valve, said regulator comprising: a housing formed of twogenerally cylindrical sections -which are adjustably secured to eachother; the first section having an inlet port which is in communicationby a passage with a cylindrical chamber in which is positioned a piston,a regulator valve in the passage between the inlet port and thecylindrical chamber, a relief valve in the piston, the relief valvehaving a portion normally contacting and holding open the regulatorvalve, an outlet port in communication with the cylindrical chamber; thesecond section having a spring which bears against the piston and acentral member which contacts the relief valve in the piston, thecentral member having a discharge passage, the magnitude of spring beingadjustable whereby the regulator valve remains open until the pressurein the cylindrical section overcomes the magnitude of the spring atwhich time the relief valve moves out of contact with the regulatorvalve closing the regulator valve; upon further incremental increase inpressure in the cylindrical chamber the piston moves further into thechamber and the relief valve contacts the central member and relievesexcess pressure through the discharge passage in the central member.

3. A pressure regulator for a hydraulic system having first and secondsections being adjustably secured one to the other, said first sectionbeing formed to define a piston chamber, a piston positioned forreciprocation in the piston chamber, an inlet port formed in the firstsection, a passageway connecting the inlet port and the piston chamber,a regulator valve disposed in the passageway and being normally biasedto a position closing said passageway, a bore formed in the piston andbeing aligned with the passageway, a relief valve positioned in thepiston bore and being movable between open and closed positions relativeto the piston bore, an outlet port formed in the first section and beingin communication with the piston chamber, a spring disposed in saidsecond section, a collar positioned on the spring and being biased bythe spring into engagement with the piston, a central member positionedfor reciprocation within the second section and having one end thereofsealingly received within the second section and the other end thereofsealingly received within the piston bore, said other end adapted tocontact the relief valve and to move the relief valve to its openposition, a discharge passage formed in the central memher.

4. A pressure regulator for a hydraulic system having first and secondsections being adjustably secured one to the other, said first sectionbeing formed to define a piston chamber, a piston positioned forreciprocation in the piston chamber, an inlet port formed in the firstsection, a passageway connecting the inlet port and the piston chamber,a regulator valve disposed in the passageway and being normally biasedto a position closing said passageway, a bore formed in the piston andbeing aligned with the passageway, a relief valve positioned in thepiston bore and being movable between open and closed positions relativeto the piston bore, the relief valve having a portion normallycontacting and holding open the regulator valve, an outlet port formedin the first section and being in communication with the piston chamber,a spring disposed in said second section, a collar positioned on thespring and being biased by the spring into engagement with the piston, acentral member positioned for reciprocation within the second sectionand having one end thereof sealingly received within the second sectionand the other end thereof sealingly received within the piston bore,said other end adapted to contact the relief valve and to move therelief valve to its open position, a discharge passage formed in thecentral member, a check valve normally closing the outlet of thedischarge passage.

5. A pressure regulator for a hydraulic system having first and secondsections in telescoping relation and being adjustably secured one to theother, said first section being formed to define a piston chamber, apiston positioned for reciprocation in the piston chamber, an inlet portformed in the first section, a passageway connecting the inlet port andthe piston chamber, a regulator valve disposed in the passageway andbeing normally biased to a position closing said passageway, a boreformed in the piston and being aligned with the passageway, a reliefvalve positioned in the piston bore and being movable between open andclosed positions relative to the piston bore, the relief valve having aportion normally contacting and holding open the regulator valve, anoutlet port formed in the first section and being in communication withthe piston chamber, a spring disposed in said second section, a collarpositioned on the spring and being biased by the spring into engagementwith the piston, stop means engageable by said collar for limitingmovement of said spring, a central member positioned for reciprocationwithin the second section and having one end thereof sealingly receivedwithin the second section and the other end thereof sealingly receivedwithin the piston bore, said other end adapted to contact the reliefvalve and to move the relief valve to its open position, a dischargepassage formed in the central member, a check valve normally closing theoutlet of the discharge passage.

6. A pressure regulator comprising a housing formed of two telescopingsections which are adjustably secured one to the other, the firstsection having an inlet port and a chamber, a passage in the firstsection connecting the inlet and the chamber, a regulator valvepositioned in the passageway and adapted to close the same, a pistonhaving a bore formed therein positioned for reciprocation within thechamber, a relief valve positioned in the piston bore for controllingthe flow of fluid through the piston bore, a regulator valve operatingmeans normally contacting and holding open the regulator valve, anoutlet port formed in the first section and being in communication withthe chamber, the second section having a spring which bears against thepiston and a central member adapted to contact the relief valve in thepiston bore, a discharge passage formed in the central member, means inthe discharge passage permitting the flow of fluid in one directiononly, the magnitude of the spring being adjustable whereby the regulatorvalve remains open until the pressure in the first section overcomes themagnitude of the spring at which time the regulator valve operatingmeans moves out of contact with the regulator valve allowing theregulator valve to close, upon further incremental increase in pressurein the chamber the piston will be moved further toward the springcausing the relief valve to be engaged and moved to its open position bythe central member to allow the excess pressure to be relieved throughthe discharge passage.

7. A pressure regulator for controlling the pressure of a fluid medium,said regulator comprising: a housing formed of two generally cylindricalsections which are adjustably secured to each other; the first sectionhaving a cylindrical chamber formed therein and having an inlet portwhich is in communication by a passage with the chamber, a pistonmovably disposed within the chamber, a regulator valve in the passagebetween the inlet port and the chamber, a relief valve in the piston inalignment with said regulator valve and normally contacting and holdingopen the regulator valve, an outlet port in communication with thechamber; the second section having a spring which bears against thepiston and normally biasing the regulator valve open and the reliefvalve closed, a central member positioned to contact the relief valve inthe piston, a discharge passage in said second section, the magnitude ofthe spring being adjustable by adjusting said cylindrical sectionswhereby the regulator valve remains open until the pressure in thesection overcomes the magnitude of the spring at which time the reliefvalve carried by said piston moves out of contact with the regulatorvalve closing the regulator valve; upon further incremental increase inpressure in the chamber the piston moves further into the chamber andthe relief valve contacts the central member and relieves excesspressure through the discharge passage.

References Cited by the Examiner UNITED STATES PATENTS 2,963,040 12/60Zimmer 137-1165 XR 2,994,334 8/61 Loveless 137116.5 XR

FOREIGN PATENTS 724,263 1/32 France.

ISADOR WEIL, Primary Examiner.

1. A PRESSURE REGULATOR FOR A CONTROL SYSTEM FOR A HYDRAULICALLYOPERATED VALVE, SAID REGULATOR COMPRISING: A HOUSING FORMED OF TWOGENERALLY CYLINDRICAL SECTIONS WHICH ARE ADJUSTABLY SECURED TO EACHOTHER BY MEANS OF MATING THREADS; THE FIRST SECTION HAVING AN INLET PORTWHICH IS IN COMMUNICATION BY A PASSAGE WITH A CYLINDRICAL CHAMBER INWHICH IS POSITIONED A PISTON, A PROPET REGULATOR VALVE IN THE PASSAGEBETWEEN THE INLET PORT AND THE CYLINDRICAL CHAMBER, A POPPET RELIEFVALVE IN THE PISTON, THE RELIEF VALVE HAVING A PORTION NORMALLYCONTACTING AND HOLDING OPEN THE REGULATOR VALVE, AN OUTLET PORT INCOMMUNICATION WITH THE CYLINDRICAL CHAMBER; THE SECOND SECTION HAVING ASPRING WHICH BEARS AGAINS THE PISTON AND A CENTRAL MEMBER WHICH CONTACTSTHE RELIEF VALVE IN THE PISTON, THE CENTRAL MEMBER HAVING A DISCHARGEPASSAGE, THE MAGNITUDE OF SPRING BEING ADJUSTABLE BY POSITIONING OF THETWO SECTIONS RELATIVE TO EACH OTHER WHEREBY THE REGULATOR VALVE REMAINSOPEN UNTIL THE PRESSURE IN THE CYLINDRICAL SECTION OVERCOMES THEMAGNITUDE OF THE SPRING AT WHICH TIME THE RELIEF VALVE MOVES OUT OFCONTACT WITH THE REGULATOR VALVE CLOSING THE REGULATOR VALVE; UPON ANYFURTHER INCRESE IN PRESSUR IN THE CYLINDRICAL CHAMBER THE PISTON MOVESFURTHER INTO THE CHAMBER AND THE RELIEF VALVE CONTACTS THE CENTAL MEMBERAND RELIEVES EXCESS PRESSURE THROUGH THE DISCHARGE PASSAGE IN THECENTRAL MEMBER.